Sparkless thermostat.



G. P. CARROLL & P. N. ROEHRIGH.

SPARKLESS THERMOSTAT.

ArgLlcATloN FILED JULY 14, 1910.

1,125,059. Pzitented Jan.19, 1915 2 SHEETS-SHEET l.

G. P. CARROLL & F. N. ROEHRIGH. SPARKLESS THERMO$TAT.

APPLICATION FILED JULY 14,1910.

1,125,059. Patented Jan.19,1915.

2 SHIBETSSHEET 2.

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GEORGE 1. CAR-R0111), 0F BRIDGEPORT, CONNECTICUT, AND FRANK N. ROEHRICH, OF JERSEY CITY, NEW JERSEY; SAID BOEHRICH'ASSIGNOR TO SAID CARROLL si'ARKLEss mnnmos'rar.

Specification of Letters Patent.

To all whom it may concern:

Be it known that we, GEORGE P. CARROLL and FRANK N. RoEHRIcH, citizens of the United States, residing, respectively, at Bridgeport, in the county of Fairfield and State of Connecticut, and at Jersey City,

blade, or of a long blade, of two metals of different coefficients of expansion and firmly fastened together so that, being pivoted at one end, the free end of the blade will move back and forth with a rise or fall of temperature" and will make slow electrical contacts first with a high temperature contact and subsequently with a low temperature contact, the electric circuit, upon either contact being made, being completed through the blade, with or without the coil, and the pivoted end. Such a device also is constructed open to the air, so that, on a contact being broken, ,a spark will jump from the contact to the receding blade end, re-

sulting in awearing away of the parts. As the contacts are slow, there is a waste of current between the making and breaking of each contact. in a cold place, as a part of a refrigerating system, moisture from the atmosphere will collect on the contacts and the blade end and will cause premature and prolonged contacts to be made. Premature and prolonged contacts are also liable to occur from particles of dirt collecting between the contacts and the blade end. Such premature and prolonged contacts seriously interfere with theaccuracy and reliability of such thermostats.

The purpose of our invention is to avoid all such difficulties by causing a tempera- 'pl'aceon the rocker device, and preferably If the thermostat is placed in its chamber, in consequence of quick tilt? ings of the rocker device, in manner as will appear. There are also certain improvements in detail as will be set forth.-

In the drawings Figure l is a partial front elevation and a partial vertical section of our invention. Fig. 2 is a vertical section through the line 22 of the preceding figure, looking toward the left, with some minor parts in elevation. Fig. 3 is an enlarged detail cross vertical section of the rocker shown at the bottom of Fig. 1 as seen through the line 33 of Fig. 6, looking toward the left, with some minor parts in elevation. Fig. 4 is a horizontal broken section through the line 41 of Fig. 1, looking from above. Fig. 5 is a plan View and Fig. 6 is-a front elevation of certain parts shown at the bottom of Fig. l.

A back frame 1, that can be screwed to any convenient vertical surface, has a frontwardly projecting base 2 and has a small round opening through it near its top and along its vertical center. Through this opening in the frame 1 and through washers 3 and 4 respectively in front and in back of the opening, projects a slotted pivot post 5, being slotted and of largest diameter in front, being-of intermediate diameter where it passes through the washer 3 and the frame 1 and being of smallest diameter where it extends through the washer 4. Pinned to the post 5 back of the washer 4 is an adjusting lever 6, extending upward. Through threaded openings in lugs 7 and 8, which extend backward from the frame 1 above the post 5, pass headed adjusting screws 9 and 10. Secured into the slot of the post 5 by a screw 11 is the inner end of a coiled band 12, constructed of two metal strips of different coeflicients of expansion; such as soft steel and brass brazed together, the brass, being the more expansive, forming the outside of the band. To the outer end of the band 12 is secured a depending trunnion bracket 16, each consisting of a bottom and upper part screwed together. Supported between these brackets by a back trunnion 17 and a front trunnion 18, passing through theupper and lower parts of Patented Jan. 19, 1915.

the brackets 15 and' 16 respectively, is a hollow rocker 19, made of tough glass and supported at its center by brass clamping bands and .21 to which the inner ends of the trunnions 17 and 18 respectively aresecured as constituent parts, the clamping bandsand will thus actuate the lever.

The inside of the bottom of the rocker 19 has secured to it a copper strip 28 forming a' patch for a copper. ball 29 to roll upon as the rocker is tilted to one side or the'other. At the extreme ends of the rocker beyond'ea ch end of the strip 28 are slight depressions 30 and 31 in which the ball rests after the rocker has been tilted into its extreme position on one side or the other. Be-' tween the center and the ends of the rocker casing on its upper side are two raised openings to which glass caps 32 and 33 are hermetically secured. From the cap 32 .at'

the left of'the center of the rocker as seen in Fig. 1 depends a copper support 35, passing through and fused into the cap, to

' which support a copper contact 36 is'pivoted, being insulated on its flat under edge and on the lower part of its broad side toward the right end of the rocker. .From

the cap 33 at the right of the centerof the rocker depends a copper'support 37, passing through and fused into the .cap, to

which support a copper contact 38 is piv oted, being insulated on its fiat under edge and on the lower part of its broad side toward the left end of the rocker. As the ball 29 rolls from the right end of the rocker it impinges against the non-insulated part of the contact 38 and lifts it up as it passes.

without coming in contact with its insulated part until it haslifted it up sufficiently to pass by. As the ball passes 'by each contact after lifting them up the contacts resume their perpendicular positions. As the ball 29 rolls from the left end of the rocker, the reverse process takes place as the contacts are passed. Through temporary. openings at 39 or 40, after the ball 29 has been inserted into'the rocker 19 and after the caps 32 and 33 have been hermetically sealed, the air is exhausted from the rocker and the openings are closed by fusion.

The bracket. 16 extends upward and has an insulated arm extending frontward through which pass copper bolts 41 and 42 to the top of which respectively are secured.

the binding posts 43 and 44. The bracket 16 also has an insulated cylinder 45 se-: cured. to its front through which the trunnion 18 passes. Inserted into the left and right of cylinder as seen in Fig. 6 are binding screws 46 and 47 respectively.

From the under end of the bolt 41 a light spring 48 coils in one direction around the cylinder 45 to the screw 47, being clamped at each end. From the screw 47 a wire 49 f screw 46, being clamped at each ehd=-. From the screw 46 a wire 51 passes in front of the rocker 19 to the copper support 35. The springs 48 and 50, being opposed to each other, have a slight tendency to keep the rocker 19 in a horizontal position. Fused into the rocker 19 so as to be contact with the strip 28 is a Wire 52 in contact atits otherv end with the band 21. A binding screw 53 is one ofthe screws holding down; the upper part of the bracket 16. As the non-insulated part of the bracket 16 is of brass, a conductive connection exists be? tween the strip 28 and a wire" 54 bound at "one endby the screw 53.

Secured to all sides of the back frame 1 is a protecting casing 55 perforated. on its sides for a free thermal action of the surrounding atmosphere onthe band 12. The

front of the casing is divided into an upper part 56, pivoted at its lower end on a rod 57 so as to open downward for free access to the band 12 and the arm 13, and into a lower part 58, projecting frontward so as to cover.

the parts supported by the base 2 and also pivoted on the rod 57 so as to open upward for free access to these parts. A coiled spring 59 on the rod 57 with projecting ends bearing on the parts 56 and 58 tends to keep the front of the casingclosed. Snap pieces 60 and 61 also normally snap into the parts 56 and 58 respectively and hold them closed. In the part 56 toward ,the right is supported an ordinary mercury glass bulb and tube thermometer 62 for observing the temperature changes. Wires 63 and 64 may lead to the binding .posts 43 and 44 respectively through insulated openings "65 and 66 respectiyely in the bottom of the casing-55; and the wire 54 may lead 'from the'"binding screw 53 through a like opening 67 in the casing 55.

- The method of operation is as follows: While the thermostat may be used to actuate any kind of temperature controlled electrical apparatus, its operation will be sufficiently understood by considering'it as a part of a temperature controlled electric refrigerating machine, such as is shown and described in the application of Carroll, filed A ril 1, 1908, Ser. No. 424,517. As-

sume t at our thermostat is placed in a nearly to 'mean temperature to be maintained.

refrigerator where it is desired to maintain a temperature ranging say from 35to 37.

of temperature approximating two degrees the striker 14 will pass from'the screw 26 to the screw"27., The, position of the arm 13 is also so .adjusted through the screws 9 and 10 that at a temperature of 36 the striker 14 will be midwaybetween the screws 26 and 27 when the latter are perfectly horizontal. The screws 26 and 27 are always used to establish-the range of temperature as desired and the screws 9 and 10 are always used to establish the The wire 64 is supposed to lead from a source of electrical supply and to be in series with an electrical device forstarting the refrigerating machine. Also the wire 63 is supposed to lead from the same supply but to be in series with an electrical device for stopping the machine. And the wire 54 is the return wire. With the parts in the positionshown in Fig. 1 the thermostat is just about to stop the machine, the temperature in the refrigerator having fallen 'ball 29 leaves the depression 31 and rolls along the strip 28 until it reaches the depression 30. This movement of the ball 29 tilts still more the rocker 19 and its rotat-' ing connections so that the screw 27 strikes against the striker 14. Meanwhile, just as the ball 29 has-begun to roll, it has struck the non-insulated part of the contact 38 and has established a brief connection be-' tween the contact 38 and the strip 28. A current now passes through the stopping device notshown, "the wire 63, the bolt 41, the spring 48, the screw 47 the wire 49, the support 37 the contact 38, the ball 29, the

' strip 28, the wire 52, the band 21, the trunnion 18, the bracket 16 and the wire. 54 to the source of supply.' With the stoppage of the machine the further movement of the striker 14 to the left ceases. When the ball 29 rolls to the left, after, the contact 38 has been lifted, it swings back to a vertical position.'- And since the contact 36 is in'sulated on its right and under side, no connection is made between this contact and the strip 28 as the ball 29 rolls to the left. Themachine having stopped and the temperature in the refrigerator beginning to rise, heat passes through the perforations As the band 12 gives up .heat, which passes through the perforain the casing 55 to the band 12. As the band 12 gradually uncoils the arm 13 begins to move to the right until the striker 14 hits the screw 27. Thereupon the lever 24, the trunnion 17 and the rocker 19 are rotated first into a perfectly horizontal position and then so that the strip 28 has a downward decline to the right. Thereupon the ball 29 leaves the depression 30 and rolls along the strip 28 until it reaches the depression 31. This reverse movement of the ball 29 tilts still more the rocker 19 and its rotating connections so that the screw 26 strikes against the striker 14 and the parts assume the position shown in Fig. 1. Meanwhile, just as the ball 29 has begun to roll, it has struck the non-insulated part of the contact 36 and has established a brief connection between the contact 36 and the strip 28. A current now passes through the startingdevices not shown, the wire 64, the bolt 42, the spring 50, the screw 46, the wire 50, the support 35, the contact 36, the ball 29, the strip 28, the wire 52, the band 21, the trunnion 18, the bracket 16 and the wire 54 to the source of supply. With the starting of the machine the further movement of the striker 14 to the right ceases. As before there is a similar swingingback to vertical positions of the contacts 36 and 38 as the ball 29 rolls to the right. And as the contact 38 is insulated on its left and under side, no connection is made between this contact and the strip 28- 'on the reverse movement of the ball 29. It

is to be noted that, in case no refrigeration takes place and the refrigerator rises to atmospheric temperature, not merely does Since the interior ofthe rocker '19 is a vacuum, it is obvious that no sparking and destructive wearing away of the parts can occur when the ball 29 leaves the contacts 38 and 36. Still less can any dust or moisture enter the rocker 19 so as to cause any premature or prolonged contacts. The briefness of the touch of the ball 29 with the contacts 38 and 36 also prevents any waste of current in the actuation of the unshown starting and stopping devices. All parts are readily accessible that require adjustment for obtaining achange of temperature range or mean.

hat we have invented and what we desire to have protected by Letters Patent is expressed in claims as follows: i

We claim: j

1. In combination 'a rocker member, a conductor, anotherconductor, each of said conductors having an'end mounted on said rocker member-,a connective member op-. erating upon a tilting of said rocker memifo ' conductor, another conductor, each of said conductors and upon a tilting of said rocker member backward to connect the ends of said second and common conductors, and

a thermostatic member operating upon a predetermined change of temperature in one direction to tilt said rocker member forward and upon a predetermined reverse change of temperature to tilt said rocker member backward.

3. In combination a rocker member, a

conductors having an end mounted on said rocker member, aconnectlve member op eratmg upon a. t1lt1ng of sa1d rocker member forward to connect said ends-and there+ I upon to break such connection, and a thermostatio member operating upon a predetermined change of temperature to so tilt said rocker member. Y

4. In combination a rocker member, a first conductor, a second conductor, a common conductor, each of said conductors having an end mounted on said rocker member, a

connective member operating upon a tilting of said rocker member forward toconnect' the ends of said first and common conduc-' tors and thereupon to break such connectionand upon a tilting of said rocker member backward to connect the ends of said {second and common conductors and there- -.ward and upon a predetermined reverse ward, and means preventing said connective 7 member from connecting said ends upon upon to break such; latter connection, and

a. thermostatic. member operating .upon a gedetenniifd change of temperature-in one rection to tilt said rocker member forchange of temperature to tilt said rocker member backward. E

5. In combmation a. rocker member, a' conductor, another conductor, each of said" -conductors having an end mounted on saidrocker member, a connective member operating ,upon a tilting ofsaid rocker member forward to connectsaid ends and there- 5 upon to break such connection, a thermostatic member operating vupon'a predeter mined change of. temperature in one direction. to tilt sa'id rocke'rmember forward and upon a predetermined reverse-change of temperature to tilt said rocker member backe such back tilting.

6. In combination. a rocker member,

mon'conductor, each of said conductors hav ing an end mounted on said rocker member, a connective member operating upon a tilt ing of said rocker member forward to conmeet the ends of said first and common conductors and thereupon to break such" connection and upon a tilting of said rocker member backward to connect the ends of said second and common conductors and thereupon to break such latter-connection, a thermostatic-member operating upon 'a predetermined change of temperature in one direction to tilt said rocker member forward and upon a predetermined reverse change of temperature to tilt said rocker member backward, and means preventing said connective member from connecting the ends of said second and common conduct'ors upon such forwardtilting and from connecting the ends of said first and common conductors uponsuch backward tilting.

7. In combination a rocker member, a conducting pathway strip mounted on said rocker member and adapted to be inclined inopposite directions successively according to the forward and backtilting .of the member, a conductor leading from said 'temperature' in one direction to tilt said rocker member forward and upon a' predetermined reverse change of temperature to reverse such tilting.

8. In combination a rockier member, a conducting pathway strip mounted on saidrocker member and adapted to-be inclinedin opposite directions successively accord, ing to the forward and back tilting of the member, a conductor leading from said strip, a conductor ball rolling forward and back along said strip according to such tilting, a-forward contact device depending from said rocker member and presenting a conducting contact surface to said ball as it so rolls forward and an insulating surface thereto as itso rolls back, a back "contact device depending from said rocker member andprescnting a conducting con-.

tact surface to said ball'asit so rollsback and an insulating; surface thereto as it 50' rolls forward, and means operating upon a predetermined change of I temperature in one direction to tilt said rodmr member tilting. I

forward and upon a predetermined reverse -9. In combinations. rocker member. con" taininga vacuum chamber, aconductor, an-

fir t conductor, a econd cpnd et rw ob; o her 9 d tq h of s nd o having an end extending from within said chamber to the outside of said rocker member, a connective member in said chamber operating upon a tilting of said rocker member forward to connect said ends, and a thermostatic member operating upon a predetermined change of temperature to so tilt said rocker member.

10. In combination a rocker member containing a vacuum chamber, a first conductor, a second conductor, a common conductor, each of said conductors having an end extending from within said chamber to the outside of said rocker member, a connective member in said chamber operating upon a tilting of said rocker member forward to connect'theends of said first and common conductors and upon a tilting of said rocker member backward to connect the ends of said second and common conductors, and a thermostatic member operating upon a predetermined change of temperature in one direction to tilt said rocker member forward and upon a predetermined reverse change of 'temperatureto tilt said rocker member backward.

11. In combination a rocker member containing a vacuum chamber, a conductor, another conductor, each of said conductors having an end extending from within said chamber to the outside of said rocker member, a connective member in said chamber operating upon a tilting of said rocker mem ber forward to connect said ends and thereupon to break such connection, and a thermostatic member operating upon a predetermined change of temperature to so tilt said rocker member.

12. In combination a rocker member containing a vacuum chamber, a first conductor, a second conductor, a common conductor, each of said conductors having an end extending from within said chamber to the outside of said rocker member, a connective member in said chamber operating upon a tilting of said rocker member forward to connect the ends of said first and common conductors and thereupon to break such connection and upon a tilting of said rocker member backward to connect the ends of said second and common conductors and having an end extending from within said chamber to the outside of said rocker memher, a connectlve member in said chamber operating upon a tilting of said rocker mem-' ber forward to connect said ends and thereupon to break such connection, a thermostatic member operating upon a predeter-- mined change of temperature in one direction to tilt said rocker member forward and /up0n a predetermined reverse change of temperature to tilt said rocker member backward, and means preventing said connective member from connecting said ends 'upon such back tilting.

14. In combination a rocker member containing a vacuum chamber, a first conductor, a second conductor, a common conductor, each of said conductors having an end extending from within said chamber to the outside of said rocker member, a connective member in said chamber operating upon a tilting of said rocker member forward to connect the ends of said first and common conductors and thereupon to break such connection and upon a tilting of said rocker member backward to connect the ends of said second and common conductors and thereupon to break such latter connection, a thermostatic member operating upon a predetermined change of temperature'in one direction to tilt said rocker member forward and upon a predetermined reverse change of temperature to tilt said rocker member backward, and means preventing said connective member from connecting the ends of said second and common conductors upon such forward tilting and from "connecting the ends of said first and common conductors u on such backward tilting.

15. n combination a rocker member containing a vacuum chamber, a conducting pathway strip in said chamber adapted to be inclined in opposite directions successively according to the forward and back tilting of said rocker member, a conductor leading from said strip to the outside of said rocker member, a conductor ball rolli'ng forward and back along said strip according to such tilting, a contact device depending from within said chamber, presenting a conducting contact surface to said ball as it so rolls forward and an insulating surface thereto as it so rolls back and having an end extending to the outside of said rocker member, and means operating upon a predetermined change of temperature in one direction to tilt said rocker member forward and upon a predetermined reverse change of temperature to reverse such .tiltin g.

16. In combination a rocker member containing a vacuum chamber, a conducting pathway strip in said chamber adapted to be inclined in opposite. directions successively according to the forward and back tilting of said rocker member, a conductor leading from said strip to the outside of said rocker member,.a conductor ball rolling forward and back along said strip according to such tilting, -a forward contact de- 40 conductors having an end extending from .within said chamber to the outside of said vice depending from within said chamber,

presenting a conducting contact surface to said ball as it so rolls forward and an insulating surface thereto as it so rolls back and having an endextending to the outside of said rocker-member, a back contact device depending from within said chamber, pre senting a conducting contact surface to said ball as it so rolls back and an insulating surface thereto as it so rolls forward, and means operating upon a predetermined change of temperature in one direction to tilt said rocker member forward and upon a predetermined reverse change of temperature to reverse such tilting.

17.'In' combination a rocker, a first con ductor, a second conductor, a common conductor, each of said conductors having an end mounted on said rocker, a connective member operating upon a tilting of said rocker forward to connect the ends of said first and common conductors and upon a tilting of. said rocker backward to connect the ends of said second and common conductors, a two arm tilting lever secured to said rocker, opposed actuating faces on said arms, a thermostatic member having a striker near said faces and operating through its striker upon a change oftemperature to a predetermined limit to force one of said faces forward until said rocker is tilted forward and upon a reverse changeof temperature to a predetermined limit to force the other of said faces backward untilthe rocker is tilted backward, and means. for positioning said strikeras desired-at a temperature midway between su'ch limits.

- 18. In combination a rocker containing a vacuum chamber, a first conductor, a second conductor, a common conductor, each of said rocker, a connective member in said chamber operating upon a tilting of said rocker forward to connect the ends of said first and common conductors and upona tilting of said rocker backward to connect the ends of a said second and' common conductors, a two arm tilting lever secured to. said rocker, opposed actuatlng faces on sald arms, a thermostatic member having a striker near said faces and operating through its striker upon a change of temperature to a redetermined limit to force one of said aces forward until said rocker is tilted'forward and upon a reverse change of temperature toa-predetermined limit to force the othenof said faces backward until the rocker is tilted,

backward, and means for positioningi said striker'as desired at atemperature midway between suchlimits I 19. In combination a rocker,- a conducts p hwa strip 1noi ted on said;- rocker change of temperature to a limit to force one of said termined limit to force the other 0 faces backward until the rocker is tilted and adapted to be inclined in opposite di-' 'rections successively according to the forward and back tilting of the rocker, a con ductor leadin from said strip, a conductor ball rolling forward and back along said strip according to such tilting, aforward contact device depending from said rocker and presenting a conducting contact surface to said ball as it so rolls forward and an 7 one of saidfaces forward until said rocker is tilted forward and upon a reverse change of temperature to a predetermined limit to force the other of said faces backward until the rocker is tilted backward, and means for positioningsaid striker as desired at a temperature mldway between such limits.

20. In combination arocker containing a vacuum chamber, a conducting pathway strip in said chamber adaptedto be inclined in opposite directions successively according to the forward and back tilting of the rocker, a conductor leading from said strip to the outside of said rocker, a conductor ball rolling forward and back along said strip according to such tilting, a forward tact surface to said ball as it so rolls forward and an insulating surface thereto as it so rolls back, a back contact device depending from within said chamber and presenting a'conducting contact surface to' said ball as-it so rolls-back and an insulating surface thereto as it so rolls forward, a two arm tilting lever? secured to said rocker,-opposed actuating faces on saidarms, a thermostatic member having astri-ker near said faces and operating through itsstriker upon a redetermined I aces forward until said rocker is tilted forward and upon a reverse change of temperature to a redesaid ' contact device depending from within said) chamber and presenting a conducting conbackward, and means for-positioning said between suchvlimits. I

' GEORGE P. CARROLL. I FRANK N. ROEHRIGI-I. Witnesses: V g a JOHN E. PRAGER, Aren'nrWfGrBBs striker as desired at a temperature midway 

